The research proposal aims to contribute to an elucidation of tonic and phasic autonomic nervous system (A.N.S.) processes that characterize several varieties of migraine. Basic hypotheses propose that some migrainous states are concomitant with deviant patterns of A.N.S. function. Pupillary reactivity of the dilator and sphincter pupillae, as indices of sympathetic and parasympathetic activity, respectively, are to be measured under several experimental conditions in a variety of migraine disorders. The experiments involve: a) The measurement of pupillary contraction in response to light and of dilatation in response to darkness. b) The measurement of the effect of stress (cold pressor test) and homeostatic recovery following its termination on pupillary dilation and pupillary contraction. c) The measurement of the effect of preventive medication on autonomic processes. The pupillometric variables will be employed to contrast patient groups, specifically patients with common migraine, classical migraine and cluster headache with each other and to nonpatient control groups. The pupillometric evaluations of A.N.S. function will be supplemented with objective personality tests and clinical rating procedures to measure changes concomitant with subjective reports of patients. Univariate and multivariate analyses of variance and covariance, multiple correlational techniques, and discriminant analysis will be employed in the analyses of the data.